JPH09188743A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for sealing semiconductors, excellent in solder heat resistance and good in preservation characteristics at normal temperatures. SOLUTION: This epoxy resin composition for sealing semiconductors consists essentially of an epoxy resin containing the one of the formula in an amount of 30-100wt.% based on the total amount of the epoxy resin, a phenol resin curing agent, a curing accelerator and fused silica. The content of the fused silica is 75-93wt.% in the whole composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation, which has excellent solder heat resistance and good room temperature storage characteristics.

[0002]

2. Description of the Related Art Conventionally, electronic parts such as diodes, transistors, and integrated circuits have been sealed with a thermosetting resin composition. Particularly, in integrated circuits, O-cresol novolac type epoxy excellent in heat resistance and moisture resistance is used. An epoxy resin composition obtained by curing a resin with a novolac type phenol resin is used. However, in recent years, as the integration of integrated circuits has increased, the size of chips has gradually increased, and the conventional DIP has been used for the package.
Small and thin flat packages that are surface mounted depending on type, SOP, TSOP, SOJ, QFP, TQFP
Etc. have changed. That is, a large chip is to be enclosed in a small and thin package, and cracks due to stress and a decrease in moisture resistance due to these cracks have been greatly highlighted. In particular, there has been a problem in that abrupt exposure to a high temperature of 200 ° C. or more in a soldering process causes a crack in a package and a peeling of a resin and a chip to deteriorate moisture resistance. Development of a highly reliable sealing resin composition suitable for sealing these large chips has been desired.

As a result of various studies in order to solve these problems, a large amount of an inorganic filler such as fused silica is blended and a low viscosity resin is used as a resin system.
The heat stress resistance at the time of soldering, that is, the solder heat resistance has been considerably improved. As the inorganic filler, by adjusting the particle size distribution and shape of the fused silica, it is possible to blend a large amount of fused silica without decreasing the fluidity,
The resin composition can have low water absorption, low thermal expansion, and high strength. Further, as the resin system, by using a relatively low molecular weight epoxy resin such as biphenyl type or naphthalene type, high adhesion, toughness, low water absorption can be achieved, and the viscosity is low. A large amount of compounding is possible. But,
The method of blending a large amount of fused silica and using a resin having a low viscosity has the following problems. This is because the resin viscosity is low and the molecular weight is low, so that the molecules move easily and the reaction easily proceeds even at room temperature, so that the room temperature storage property is deteriorated. That is, when the resin composition is stored at room temperature, the fluidity decreases, and therefore, the gold wire is deformed during molding.
Problems such as island shift and defective filling occur.
Therefore, it has good room temperature storage characteristics and excellent solder heat resistance.
Development of a resin composition for sealing has been desired.

[0004]

SUMMARY OF THE INVENTION The present invention addresses the above problems by using an epoxy resin of the formula (1), which has excellent solder heat resistance and good room-temperature storage characteristics. An epoxy resin composition for use is provided.

[0005]

The present invention provides (A) an epoxy resin containing the epoxy resin represented by the following formula (1) in an amount of 30 to 100% by weight based on the total amount of the epoxy resin, and (B) a phenol resin curing agent. An epoxy resin composition for semiconductor encapsulation, comprising (C) a curing accelerator, and (D) fused silica as essential components, and containing 75 to 93% by weight of the fused silica in the entire composition. is there.

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The epoxy resin represented by the formula (1) has particularly good room temperature storage characteristics as compared with the epoxy resins represented by the formulas (2) and (3). Further, it has excellent properties such as low water absorption, adhesiveness, strength under heat, and solder heat resistance. Equation (1)
By adjusting the amount of the epoxy resin used, which is shown in FIG. 3, the room temperature storage characteristics and the solder heat resistance can be maximized. In order to bring out the effect, it is desirable to use the epoxy resin represented by the formula (1) in an amount of 30% by weight or more, preferably 50% by weight or more based on the total amount of the epoxy resin. If it is less than 30% by weight, the room temperature storage property or the solder heat resistance is deteriorated.

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Embedded image When an epoxy resin other than the epoxy resin of the formula (1) is used in combination, the epoxy resin used is any polymer having an epoxy group, and examples thereof include bisphenol type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, There are trifunctional epoxy resins such as phenol novolac type epoxy resins and triphenol methane type epoxy resins, alkyl modified triphenol methane type epoxy resins and the like, triazine nucleus-containing epoxy resins and the like, and these may be used alone or in combination.

The phenol resin curing agent used in the present invention is
It is a general polymer having a phenolic hydroxyl group, and examples thereof include phenol novolac resin, cresol novolac resin, phenol aralkyl resin, dicyclopentadiene modified phenol resin, and terpene modified phenol resin. These resins may be used alone or as a mixture.

The curing accelerator used in the present invention may be any one as long as it accelerates the reaction between the epoxy group and the phenolic hydroxyl group, and those generally used for sealing materials can be widely used. 1,8-diazabicycloundecene, triphenylphosphine, benzyldimethylamine, 2-methylimidazole, and the like, and these may be used alone or in combination.

Examples of the fused silica used in the present invention include crushed fused silica and spherical fused silica, and the blending amount thereof is 75 to 93% by weight based on the total composition. If it is less than 75% by weight, water absorption and thermal expansion increase, and solder heat resistance is insufficient.
When it exceeds 93% by weight, fluidity is lowered and moldability is deteriorated.

The encapsulating epoxy resin composition of the present invention contains an epoxy resin, a phenol resin curing agent, a curing accelerator, and fused silica as essential components. In addition to these, a silane coupling agent and bromine may be added if necessary. Flame retardants such as epoxidized epoxy resin, antimony trioxide and hexabromene, coloring agents such as carbon black and red iron oxide, mold release agents such as natural wax and synthetic wax, and low stress additives such as silicone oil and rubber. There is no problem even if additives are properly mixed. Further, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, an epoxy resin, a phenol resin curing agent, a curing accelerator, fused silica, and other additives are sufficiently uniformly mixed with a mixer or the like. After that, the mixture can be further melt-kneaded with a hot roll or a kneader, cooled and pulverized to obtain a molding material. These molding materials can be applied to the sealing of electronic parts or electric parts, coating insulation, and the like.

[0011]

The present invention will be specifically described below with reference to examples. Example 1-Epoxy resin represented by the following formula (1): 8.80 parts by weight-Phenol novolac resin curing agent: 6.15 parts by weight (softening point 85 ° C, hydroxyl group equivalent 105) -1,8-diazabicyclo (5 , 4,0) Undecene-7 (DBU): 0.25 parts by weight Spherical fused silica (average particle size 15 μm): 84.00 parts by weight Carnauba wax: 0.50 parts by weight Carbon black: 0.30 parts by weight The parts were mixed in a mixer at room temperature, kneaded with a biaxial roll at 80 to 100 ° C., cooled and pulverized to obtain a molding material. Spiral flow, normal temperature storage stability, solder crack resistance and solder moisture resistance test of the obtained molding material were carried out. Table 1 shows the evaluation results.

<Evaluation method> Spiral flow: A mold for spiral flow measurement conforming to EMMI-I-66 was used, and the mold temperature was 175 ° C.
The measurement was performed at an injection pressure of 70 kg / cm ² and a curing time of 2 minutes. -Room temperature storability: The spiral flow was measured after the resin composition was stored at 25 ° C for 1 week. The ratio is shown in% when the initial spiral flow length is 100%.・ Solder cracking property: 52pQ with chip size 6 × 6mm
FP mold temperature 175 ° C., injection pressure 70 kg / cm ² ,
Molded with a curing time of 2 minutes,
Post cured in time. This molded product was treated in an environment of 85 ° C and 85% RH for 48 hours, 72 hours, and 120 hours, and then immersed in a solder bath at 260 ° C for 10 seconds, and then the total number was 1 using a microscope.
Six external cracks were observed and expressed by the number of cracks in 16 cracks.・ Solder moisture resistance: 52pQFP with chip size 6 × 6mm
Was molded at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes, and the obtained molded product was post-cured at 175 ° C. for 8 hours. This molded product was treated for 72 hours in an environment of 85 ° C. and 85% RH, then immersed in a solder bath at 260 ° C. for 10 seconds, and then subjected to a pressure cooker test (125 ° C., 100 ° C.).
% RH) to measure the open circuit failure of the circuit.

<< Examples 2 to 5, Comparative Examples 1 to 6 >> According to the formulations shown in Tables 1 and 2, molding materials were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2. The epoxy resins used in Examples and Comparative Examples have the structural formulas of Formula (1), Formula (2) and Formula (3), and the orthocresol novolac type epoxy resin has a softening point of 65 ° C. An epoxy equivalent of 200 was used.

Table 1 Example 1 2 3 4 5 Compounding (parts by weight) Epoxy resin of the formula (1) 8.80 5.41 3.66 5.19 5.50 Epoxy resin of the formula (2) 3.61 5.48 Epoxy resin of the formula (3) 3.46 Orthocresol-rnovolak epoxy resin 3.67 Phenol -Lunovolac resin curing agent 6.15 5.93 5.81 6.30 5.78 DBU 0.25 0.25 0.25 0.25 0.25 Spherical fused silica 84.00 84.00 84.00 84.00 84.00 Carnauba wax 0.50 0.50 0.50 0.50 0.50 Carbon black 0.30 0.30 0.30 0.30 0.30 Characteristic spiral flow (cm) 96 98 93 84 85 Room temperature Storability (%) 92 89 86 85 93 Solder crack resistance Moisture absorption 48 hours 0 0 0 0 0 (Number of cracks / 16 pieces) Moisture absorption 72 hours 0 0 0 0 0 Moisture absorption 120 hours 0 0 0 0 4 Solder moisture resistance Average life ( Time) ＞ 500 ＞ 500 ＞ 500 ＞ 500 ＞ 500

Table 2 Comparative Example 1 2 3 4 5 6 Compounding (parts by weight) Epoxy resin of the formula (1) 1.85 14.68 2.91 Epoxy resin of the formula (2) 9.38 7.41 Epoxy resin of the formula (3) 8.44 Orthocresol-Renovolak epoxy resin 9.80 Phenol- Lunovolac resin curing agent 5.57 6.51 5.15 5.69 10.27 2.04 DBU 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Spherical fused silica 84.0 84.0 84.0 84.0 74.0 94.0 Carnauba wax 0.50 0.50 0.50 0.50 0.50 0.50 Carbon black 0.30 0.30 0.30 0.30 0.30 0.30 Characteristics Spiral flow (cm) 94 72 69 97 143 28 Storage at room temperature (%) 77 69 94 78 92 89 Solder cracking property Moisture absorption 48 hours 0 0 0 0 1 0 (Number of cracks / 16 pieces) Moisture absorption 72 hours 0 0 7 7 0 5 0 Moisture absorption 120 hours 0 0 16 0 16 0 Solder moisture resistance Average life (hours) ＞ 500 ＞ 500 250 ＞ 500 350 ＞ 500

[0017]

EFFECTS OF THE INVENTION According to the present invention, a resin composition having excellent solder heat resistance can be obtained, and the ordinary temperature storage property, which is a conventional defect, is excellent. Therefore, it is extremely useful as a resin composition for surface mounting semiconductor encapsulation. The industrial value is enormous.

Claims (1)

[Claims] 1. An epoxy resin containing (A) an epoxy resin represented by the following formula (1) in an amount of 30 to 100% by weight based on the total amount of epoxy resin, (B) a phenol resin curing agent, and (C).
An epoxy resin composition for semiconductor encapsulation, comprising a curing accelerator and (D) fused silica as essential components, and 75 to 93 wt% of the fused silica in the total composition. Embedded image